[Quickfix-developers] Latency & Quickfix/J
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From: Ian J. <Ian...@bt...> - 2006-01-23 19:14:44
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Version 1.0.0 b2 (Jan 06) Hi, Does anyone know how i might control TCP options and/or buffering in = Quickfix/J? I realise that the current version is implemented over netty = and I don't know how/if it can be configured. Options i am interested in = are send/receive buffering and TCP_NODELAY. I understand that incorrect use of these options can affect throughput = adversely, but i am trying to address latency of updates at lower = message volumes. Does anyone have any other suggestions of where latency in message = transmission and/or reception can be addressed? An example of the scale of my problem is that i am experiencing "jitter" = in messages (MarketDataIncrementalRefresh) sent fairly constantly. At rates of 15-20 msg/sec (around 3-4k bytes per second), the jitter is = 2-300ms.=20 At rates of 60-70 msg/sec (around 12-15k), the jitter is still 100+ ms Its not until throughput increases significantly that the latency = becomes less significant (2-250 msg/sec), the jitter is < 50ms I am using enhanced Java 1.5 precision timers, so timings have = granularity of better than 1 ms (my measurement threshold) I have implemented SystemTimeSource to use System.nanoTime() (with mods) = and time the SendingTime FIX stamp (with ms) to received delay. The = absolute delay is not relevant (due to mismatched clocks) - i am just = looking at the variation in delay from msg to msg.=20 The server/client are in US/UK, and normal ping times between them are = approx 80ms (and pretty solid), available bandwidth is up to 1Mb. Does anyone have any experience of how this jitter will be affected by = SSL tunnelling (stunnel). I don't have control over the sender but can = affect "tuning" of stunnel parameters at either end.=20 |